rf_pqdeg.c revision 1.10 
1/*	$NetBSD: rf_pqdeg.c,v 1.10 2023/10/15 18:15:20 oster Exp $	*/
2/*
3 * Copyright (c) 1995 Carnegie-Mellon University.
4 * All rights reserved.
5 *
6 * Author: Daniel Stodolsky
7 *
8 * Permission to use, copy, modify and distribute this software and
9 * its documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
15 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
16 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
21 *  School of Computer Science
22 *  Carnegie Mellon University
23 *  Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 */
28
29#include <sys/cdefs.h>
30__KERNEL_RCSID(0, "$NetBSD: rf_pqdeg.c,v 1.10 2023/10/15 18:15:20 oster Exp $");
31
32#include "rf_archs.h"
33
34#if (RF_INCLUDE_DECL_PQ > 0) || (RF_INCLUDE_RAID6 > 0)
35
36#include <dev/raidframe/raidframevar.h>
37
38#include "rf_raid.h"
39#include "rf_dag.h"
40#include "rf_dagutils.h"
41#include "rf_dagfuncs.h"
42#include "rf_dagffrd.h"
43#include "rf_dagffwr.h"
44#include "rf_dagdegrd.h"
45#include "rf_dagdegwr.h"
46#include "rf_etimer.h"
47#include "rf_pqdeg.h"
48#include "rf_general.h"
49#include "rf_pqdegdags.h"
50#include "rf_pq.h"
51
52/*
53   Degraded mode dag functions for P+Q calculations.
54
55   The following nomenclature is used.
56
57   PQ_<D><P><Q>_Create{Large,Small}<Write|Read>DAG
58
59   where <D><P><Q> are single digits representing the number of failed
60   data units <D> (0,1,2), parity units <P> (0,1), and Q units <Q>, effecting
61   the I/O. The reads have only  PQ_<D><P><Q>_CreateReadDAG variants, while
62   the single fault writes have both large and small write versions. (Single fault
63   PQ is equivalent to normal mode raid 5 in many aspects.
64
65   Some versions degenerate into the same case, and are grouped together below.
66*/
67
68/* Reads, single failure
69
70   we have parity, so we can do a raid 5
71   reconstruct read.
72*/
73
74RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateReadDAG)
75{
76	rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
77}
78/* Reads double failure  */
79
80/*
81   Q is lost, but not parity
82   so we can a raid 5 reconstruct read.
83*/
84
85RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateReadDAG)
86{
87	rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_pRecoveryFuncs);
88}
89/*
90  parity is lost, so we need to
91  do a reconstruct read and recompute
92  the data with Q.
93*/
94
95RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateReadDAG)
96{
97	RF_PhysDiskAddr_t *temp;
98	/* swap P and Q pointers to fake out the DegradedReadDAG code */
99	temp = asmap->parityInfo;
100	asmap->parityInfo = asmap->qInfo;
101	asmap->qInfo = temp;
102	rf_CreateDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList, &rf_qRecoveryFuncs);
103}
104/*
105  Two data units are dead in this stripe, so we will need read
106  both P and Q to reconstruct the data. Note that only
107  one data unit we are reading may actually be missing.
108*/
109RF_CREATE_DAG_FUNC_DECL(rf_CreateDoubleDegradedReadDAG);
110RF_CREATE_DAG_FUNC_DECL(rf_CreateDoubleDegradedReadDAG)
111{
112	rf_PQ_DoubleDegRead(raidPtr, asmap, dag_h, bp, flags, allocList);
113}
114RF_CREATE_DAG_FUNC_DECL(rf_PQ_200_CreateReadDAG);
115RF_CREATE_DAG_FUNC_DECL(rf_PQ_200_CreateReadDAG)
116{
117	rf_CreateDoubleDegradedReadDAG(raidPtr, asmap, dag_h, bp, flags, allocList);
118}
119/* Writes, single failure */
120
121RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateWriteDAG);
122RF_CREATE_DAG_FUNC_DECL(rf_PQ_100_CreateWriteDAG)
123{
124	if (asmap->numStripeUnitsAccessed != 1 &&
125	    asmap->failedPDAs[0]->numSector !=
126	    raidPtr->Layout.sectorsPerStripeUnit)
127		RF_PANIC();
128	rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp,
129		      flags, allocList, 2,
130		      (void (*) (RF_DagNode_t *)) rf_Degraded_100_PQFunc,
131		      RF_FALSE);
132}
133/* Dead  P - act like a RAID 5 small write with parity = Q */
134RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateSmallWriteDAG)
135{
136	RF_PhysDiskAddr_t *temp;
137	/* swap P and Q pointers to fake out the DegradedReadDAG code */
138	temp = asmap->parityInfo;
139	asmap->parityInfo = asmap->qInfo;
140	asmap->qInfo = temp;
141	rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags,
142				     allocList, &rf_qFuncs, NULL);
143}
144/* Dead Q - act like a RAID 5 small write */
145RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateSmallWriteDAG)
146{
147	rf_CommonCreateSmallWriteDAG(raidPtr, asmap, dag_h, bp, flags,
148				     allocList, &rf_pFuncs, NULL);
149}
150/* Dead P - act like a RAID 5 large write but for Q */
151RF_CREATE_DAG_FUNC_DECL(rf_PQ_010_CreateLargeWriteDAG)
152{
153	RF_PhysDiskAddr_t *temp;
154	/* swap P and Q pointers to fake out the code */
155	temp = asmap->parityInfo;
156	asmap->parityInfo = asmap->qInfo;
157	asmap->qInfo = temp;
158	rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags,
159				     allocList, 1, rf_RegularQFunc, RF_FALSE);
160}
161/* Dead Q - act like a RAID 5 large write */
162RF_CREATE_DAG_FUNC_DECL(rf_PQ_001_CreateLargeWriteDAG)
163{
164	rf_CommonCreateLargeWriteDAG(raidPtr, asmap, dag_h, bp, flags,
165				     allocList, 1, rf_RegularPFunc, RF_FALSE);
166}
167
168
169/*
170 * writes, double failure
171 */
172
173/*
174 * Lost P & Q - do a nonredundant write
175 */
176RF_CREATE_DAG_FUNC_DECL(rf_PQ_011_CreateWriteDAG)
177{
178	rf_CreateNonRedundantWriteDAG(raidPtr, asmap, dag_h, bp, flags, allocList,
179	    RF_IO_TYPE_WRITE);
180}
181/*
182   In the two cases below,
183   A nasty case arises when the write a (strict) portion of a failed stripe unit
184   and parts of another su. For now, we do not support this.
185*/
186
187/*
188  Lost Data and  P - do a Q write.
189*/
190RF_CREATE_DAG_FUNC_DECL(rf_PQ_110_CreateWriteDAG)
191{
192	RF_PhysDiskAddr_t *temp;
193
194	if (asmap->numStripeUnitsAccessed != 1 &&
195	    asmap->failedPDAs[0]->numSector != raidPtr->Layout.sectorsPerStripeUnit) {
196		RF_PANIC();
197	}
198	/* swap P and Q to fake out parity code */
199	temp = asmap->parityInfo;
200	asmap->parityInfo = asmap->qInfo;
201	asmap->qInfo = temp;
202	rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
203		      allocList, 1,
204		      (void (*) (RF_DagNode_t *)) rf_PQ_DegradedWriteQFunc,
205		      RF_FALSE);
206	/* is the regular Q func the right one to call? */
207}
208/*
209   Lost Data and Q - do degraded mode P write
210*/
211RF_CREATE_DAG_FUNC_DECL(rf_PQ_101_CreateWriteDAG)
212{
213	if (asmap->numStripeUnitsAccessed != 1 &&
214	    asmap->failedPDAs[0]->numSector != raidPtr->Layout.sectorsPerStripeUnit)
215		RF_PANIC();
216	rf_CommonCreateSimpleDegradedWriteDAG(raidPtr, asmap, dag_h, bp, flags,
217	    allocList, 1, rf_RecoveryXorFunc, RF_FALSE);
218}
219#endif				/* (RF_INCLUDE_DECL_PQ > 0) ||
220				 * (RF_INCLUDE_RAID6 > 0) */
221